Spring.



G. WATSON & R. A. S. PAGET.

} SPRING. APPLICATION FILED JAN. 9, 1911.

Patented May 23, 1911.

Fig.4.

INVEN TORS UNITED STATES PATENT OFFICE.

CECIL WATSON AND RICHARD ARTHUR SURTEES PAGET, OF LONDON, ENGLAND.

SPRING.

Specification of Letters Patent.

Application filed January 9, 1911.

Patented May 23, 1911.

Serial No. 601,728.

To all whom it may concern:

Be it known that we, CECIL IVA'rsoN, associate member of the Instituteof Civil Engineers, and RICHARD ARTHUR Sonrnus PAGET, baronet, bothsubjects of His Majesty the King of Great Britain, and residents ofLondon, England, have invented a certain new and useful Improvement inSprings, of whichthe following is a specification.

This invention relates to improvements in coiled helical springs forrailway buffing and draw gear and other purposes in which springs aresubjected to varying compressional stresses, and in particular tostresses sufiicient to bring the coils in contact with one another, andhas for its object the prevention of the relative rotation of theextremities which normally occurs during the compression and naturalextension of coil springs; compression tending to rotate the extremitiesof the spring in one direction and extension in the opposite direction.In the case of buffing and draw springs of railway and other rollingstock, this action has an injurious effect subjecting the bufling anddraw gear to constant torsional strains which cause wear and tear, andtends to twist the bufler head and draw hook. Any mechanical device forresisting rotation necessarily subjects the spring to distortion. Theuse of pairs or nests of concentric right and left hand springs does notavoid the difliculty, for each individual spring tends to rotate and istherefore subject to strain if rotation is prevented, or causes wear onthe ends of the springs and the surfaces against which they abut ifrotation is permitted, while the unequal size of the concentric springsmakes it practically impossible for them to have equal rotation.

In the accompanying drawings :Figure 1 represents a ortion of anordinary bar from which it 1s desired to form a helical spring accordingto this invention; Fig. 2 shows said bar bent on itself; Fig. 3 showshow said bar may be hammered out so as to present an even surfacecorresponding to the angle between the right and left hand coils to bemade; Fi 4 is a similar view to Fig. 1, except that t e bar is shownthickened at the bendin point as shown by Fig. 5, which permits a ongerpoint to be forged out as shown in Fig. 6; and Fig. 7 represents acoiled spring formed from V bars as shown in Fig. 3 or 6.

According to this invention, each complete spring is composed of twoinverse and preferably equal and opposite co-axial coils, A and B asshown in Fig. 7 so shaped at their inner ends 0 as to form in effect asingle right and left hand coil of which the rotation of one half Apractically neutraL izes the rotation of the other, 13 so that therelative rotation at the outer ends is m'l. Springs according to thisinvention, t. 0. free from liability to twist and capable of resistingstress in excess of their working capacity. may be made for example bycoiling a V-shaped bar, as for example a straight bar as shown in Fig. 1turned back on itself at the center as shown in Fig. 2 and shaped ashereafter described around a mandrel.

The V-shaped bar is so formed with a wedge-shaped end as shown in Figs.3 and 6 that after being coiled into a right and left hand spring thecoils when compressed home bear evenly on one another in true alinementand the end faces of the spring are in planes at right angles to thecenter line of the spring, the conditions being similar to those of twoseparate oppositely coiled springs with their inner bases coinciding.For this purpose the angle D of the V-shaped bar and of its wedge-shapedend F must be so formed that when, after coiling, the two members G andH of the V are compressed together so as to be in contact from the pointof bifurcation to the point at which the outer surfaces of thewedge-shaped end would, if prolonged, meet at a point, the outersurfaces form similar helical curves of pitch equal to that of the rightand left hand helices A and B. For instance assume the angle of thehelix of the right and left hand coils to be 5 when compressed home thenthe wedge shaped end is tapered out to roughly correspond with thisangle so that when the whole spring is compressed home all the coils bedfairly on one another.

In the ideal arrangement the helices are at their full section up to thepoint of bifurcation, the V-shaped bar being initially thickened asshown at I, Figs. 4 and 5 at the center and then bent into V form, thethickened portion being forged out into a wedgeshaped end with helicalsurfaces as above described. We have found, however, that for practicalpurposes it is feasible to form the V from a bar without initialthickening in the center, the bar in this case being bent and formedinto a V with helical surfaces and wedge-shaped end as above describedby tapering the coils as shown in Figs. 3 and 6 toward the point ofbifurcation so that a portion of the wedge is as it were bisected alonga plane transverse to the aXis of the helices so as to form separatecoils tapering in depth toward the end of the wedge and having theirinner surfaces in contact even when the spring is uncompressed.Experiment has proved that such tapering though it weakens the spring inrespect to its resistance to lateral strain in no way weakens it inrespect to its resistance to compression or even to the strains set upwhen the coils are compressed home while the omission of the initialthickening materially reduces the cost of manufacture.

It has heretofore been proposed to use double volute springs made in onepiece with the coils of one half of the spring inclined in an oppositedirection to that of the other half, though not for the purposedescribed in this specification as with such volute springs the pointwhere they join takes no part of the direct thrust when compressed. Ithas also been proposed to employ separate oppositely coiled helicalsprings for the purpose of neutralizing rotation but this proposalnecessitates the introduction of means for coupling same and does notobviate the possibility of two rightor two left hand springs beingerroneously coupled while the essence of this invention is thecombination in a single spring of two equal and inverse helical coilswhose inner ends merge into a single wedge-shaped end of double helicalform as described.

The wedgeshaped end may be truncated if desired so as to reduce theamount of drawing out, provided that the wedge portion be of sufficientlength to give adequate support to the adjacent coils when compressedhome.

lVhat we claim is:

A right and left hand spring for resisting compression and preventingend rotation, having two equal and opposite co-aXial helices in the sameplanes and terminating at their inner extremities in a single wedgeshaped end of helical form and in plane with the helices.

In testimony whereof we have hereunto set our hands in the presence oftwo subscribing witnesses.

CECIL WATSON. RICHARD ARTHUR SURTEES PAGET.

Witnesses E. THOMPSON, W. W. JoNEs.

Copies 'of this patent may be obtained for five cents each, byaddressing the Commissioner of Patents, Washington, D. C.

